This application claims priority under 35 U.S.C. §119 (a) on Patent Application No. 2011-183917 filed in Japan on Aug. 25, 2011, the entire contents of which are herein incorporated by reference.
The present invention relates to an image forming apparatus (e.g., a copier, a multifunction peripheral, and a printer), a processing unit, and an image forming method.
In a conventional image forming apparatus, typically, an image forming portion forms an obtained image on an image formation target such as an image carrier or a transfer target. For example, image formation according to an electrophotographic method is performed by charging a surface of an image carrier such as a photosensitive member that functions as an image formation target, exposing an image to the charged surface to form an electrostatic latent image, making visible (developing) the electrostatic latent image as a toner image, electrostatically transferring the visible toner image to an intermediate transfer member or a recording sheet such as a recording paper, and, if transferring the toner image to the intermediate transfer member, further transferring that image to a recording sheet.
Examples of such image forming apparatuses include an image forming apparatus in which a coating process that forms a coating film made of resin or the like is performed on a recording sheet that is being transported on a transport path for transporting (discharging) a recording sheet with an image formed thereon.
Incidentally, in an image forming apparatus that performs the coating process, the coating process speed (the transport speed at which a recording sheet is transported when performing the coating process on the recording sheet with an image formed thereon) is typically lower than the transport speed at which a recording sheet that is subjected to an image formation process that does not include a coating process is transported (discharged).
Since the transport speed of a recording sheet that requires the coating process is lower than the transport speed of a recording sheet that does not require the coating process, when transporting the recording sheet that does not require the coating process after the recording sheet that requires the coating process, the recording sheet that does not require the coating process has to be put on standby until the coating process ends. For example, if one job involves a recording sheet that requires the coating process and a recording sheet that does not require the coating process in a mixed manner, the succeeding recording sheet that does not require the coating process is put on standby for the preceding recording sheet that requires the coating process in that job. Furthermore, if the coating process is to be performed on a recording sheet in one job and the coating process is not to be performed on a recording sheet in another job, the succeeding job that does not require the coating process is put on standby for the preceding job that requires the coating process.
In this manner, in an image forming apparatus that performs the coating process, the processing time (throughput time) from when transport of a recording sheet that does not require the coating process starts to when the transport ends after image formation deteriorates when the coating process is performed.
With respect to this point, JP 2003-103880A discloses a printed material transporting apparatus, including a receiving end configured to receive, from a printing apparatus (image forming apparatus), a printed material (recording sheet) after printing (image formation) by the printing apparatus, the receiving end facing a discharging end of the printing apparatus, wherein the transporting apparatus transports the received printed material from the receiving end to a feeding end of a laminating apparatus (coating portion). In this configuration, the printed material after the printing by the printing apparatus is discharged to a transfer guide plate, and the printed material after the lamination process is discharged to a discharge tray.
However, in the configuration described in JP 2003-103880A, since a recording sheet that does not require the coating process and a recording sheet that has undergone the coating process are discharged to trays (specifically, the transfer guide plate and the discharge tray) arranged on different transport paths, there is a problem in which the recording sheet that has undergone the coating process and the recording sheet that does not require the coating process are discharged to different trays. For example, when performing the image formation on a plurality of recording sheets and further performing the coating process on part of the plurality of recording sheets in one job, pages of the recording sheets in that job cannot be aligned with each other.
It is an object of the present invention to provide an image forming apparatus, a processing unit, and an image forming method with which, when performing a coating process that forms a coating film on a recording sheet with an image formed thereon, the processing time (throughput time) from when transport of a recording sheet that does not require the coating process starts to when the transport ends after image formation can be effectively prevented from deteriorating, and, moreover, in which the recording sheet that has undergone the coating process and the recording sheet that does not require the coating process can be transported to the same transport path.